What's the difference between alkaloid and picrotoxin?
Alkaloid
Definition:
(a.) Alt. of Alkaloidal
(n.) An organic base, especially one of a class of substances occurring ready formed in the tissues of plants and the bodies of animals.
Example Sentences:
(1) Thus, alkaloid and insecticide modifications share many features but differ in how much the conducting properties of the pore are changed and whether the channel can close reversibly while the toxin remains bound.
(2) A clear structure-mutagenicity relationship was observed in a series of aporphine alkaloids (aporphine, dehydroaporphine, 7-oxoaporphine and 4,5-dioxoaporphine), and 10,11-non-substituted aporphines were suggested to exert their mutagenicity through metabolic activation of the 10,11 positions, possibly as the 10,11-epoxides.
(3) A radioactive, photoactive Vinca alkaloid, N-(p-azido-[3,5-3H]-benzoyl)-N'-beta-aminoethylvindesine [( 3H]NABV) with pharmacological and biological activities similar to vinblastine was synthesized and used to identify specific Vinca alkaloid macromolecular interactions in calf brain homogenate by photoaffinity labeling.
(4) The comparative metabolism of the pyrrolizidine alkaloid (PA) senecionine was studied in vitro in incubations of rat, guinea pig, cow, horse, and sheep hepatic microsomes.
(5) They also displayed negative correlation between activities of protein-inhibitors and the total content of protein and alkaloids.
(6) Methods have been reviewed for alkylating agents, platinum compounds, antitumour antibiotics, antimetabolites, alkaloids, suramin, 1-hydroxy-3-amino-propylidene-1,1-bisphosphonate and tamoxifen.
(7) The resistant strains exhibited cross resistance to anthracycline antibiotics, vinca alkaloids, actinomycin D, colchicine.
(8) In mice treated with cepharanthine (Cepha), a biscoclaurine alkaloid, the number of T cells was increased in the parathymic lymph nodes (PtLNs) which are considered to be the specialized lymph nodes in local differentiation of T cells.
(9) The alkaloid tubulosine inhibits the process of peptide chain elongation by eukaryotic polysomes by specifically preventing the elongation-factor-2-dependent step of translocation.
(10) Cultured roots of Stephania cepharantha, which are rich sources of bisbenzylisoquinoline alkaloids, were fed 14C-labelled tyrosine, tyramine or dopamine.
(11) As a possible mechanism underlying the alterations of DRP, the functional consequences of atrophic changes of primary central afferent terminals are being discussed in terms of the close correlation between structure and function and the possible inferences of the electrophysiological reaction to the therapeutic application of Vinca alkaloids in the iontophoretic treatment of chronic intractable pain.
(12) The poisonous principles in tansy ragwort are pyrrolizidine alkaloids, which cause gradual alteration and necrosis of liver cells with replacement by fibrous tissue.
(13) In this study, the roots of Tabernaemontana heyneana Wall were examined and the isolation and identification of additional indole alkaloids and some pharmacological properties of coronaridine are described.
(14) The area ratios of four alkaloids (tropacocaine, norcocaine, cis-cinnamoylcocaine, and trans-cinnamoylcocaine) to cocaine are calculated for each sample.
(15) The main drugs with specific action on migraine include ergot alkaloids (ergotamine, dihydroergotamine), agonists (sumatriptan) or partial agonists (methysergide) at a specific subtype of 5-HT1-like receptors, beta-adrenoceptor antagonists (propranolol, metoprolol), calcium antagonists (flunarizine) and anti-inflammatory agents (indomethacin).
(16) Effects of solution variables on the binding and self-association explain the wide variation of reported apparent binding constants for Vinca alkaloids to tubulin.
(17) The concomitance of five previously reported trans-2,5-dialkyl-pyrrolidines along with small amounts of the cis isomers and N-methyl analogues makes the venom of M. indicum the most qualitatively diverse blend of alkaloids reported from an ant to date.
(18) Strong enhancement of delayed-type hypersensitivity (DTH) was observed after treatment with the active cyclophosphamide (CY) derivative Z 7557 or the plant alkaloid VP-16 at the site of sensitization.
(19) A total alkaloid and two purified alkaloid extracts of Alangium Vitiense were revealed by our experimental screening to be oncostatic on L1210 leukemia and two other lymphoid neoplasias in Mice.
(20) Possible mechanisms underlying these effects of insecticides on alkaloid-dependent uptake are discussed in light of a qualitative model formulated from these results and previous biochemical and electrophysiological studies.
Picrotoxin
Definition:
(n.) A bitter white crystalline substance found in the cocculus indicus. It is a peculiar poisonous neurotic and intoxicant, and consists of a mixture of several neutral substances.
Example Sentences:
(1) Other characteristics of the LHP that were demonstrated include: a lack of blockage by GABAA receptor antagonists, a probable voltage sensitivity (decrease in amplitude in the depolarizing direction), and an apparent brief onset latency (less than 10 ms) when the early IPSP was blocked by picrotoxin.
(2) The results are interpreted as follows: picrotoxin released dopamine through disinhibition of the dopaminergic neurons as a result of blockade of gabergic receptors.
(3) This conductance increase was blocked by picrotoxin over a range of concentrations similar to those required for blockade of the GABA-induced response.
(4) Picrotoxin (50 microM) induced spontaneous bursts of repetitive spiking, followed by a slow, negative field potential, associated with spreading depression (SD), in slices from immature animals.
(5) 's are reversibly abolished by the application of picrotoxin and gamma-aminobutyric acid.
(6) The response was blocked by picrotoxin in a noncompetitive manner.
(7) However, picrotoxin and beta-guanidinopropionic acid block the response to pressure-applied GABA but do not block the response to light even at an order of magnitude higher concentration.
(8) Synchronous firing was initiated by stimulating stratum radiatum fibers in the presence of picrotoxin.
(9) The effect of baclofen was antagonized by a low dose of 4-aminopyridine (5 X 10(-6) M) whereas it was unaffected by picrotoxin (2 X 10(-5) M).
(10) 5 alpha-Pregnan-3 alpha-ol-20-one protected mice against metrazol-, bicuculline- and picrotoxin-induced seizures but not against electroshock-and strychnine-induced seizures.
(11) Putative blockers of the GABA-receptor coupled chloride channel, picrotoxin and pentylenetetrazol, and the benzodiazepine receptor antagonists Ro 15-1788 and CGS 8216 each blocked the anxiolytic effect of chlordiazepoxide.
(12) It is possible that Ro 5-4864 exerts its convulsant action at the picrotoxin site of the central Bz receptor - gamma-aminobutyric acid receptor-chloride ionophore complex.
(13) Implants containing 10% estradiol in cholesterol were less effective in protecting against picrotoxin-induced seizures.
(14) injection of hypertonic solutions of GABA and mannitol on convulsant activity and latency to reduced or enhanced depending on whether picrotoxin was given i.p.
(15) From a comparison of activation by strychnine and picrotoxin in normal and chronically decapitated embryos it was deduced that a spinal and a supraspinal component participated in their effect.
(16) The locomotion reducing effects of naloxone could be blocked by either picrotoxin or bicuculline.
(17) The GABA receptor antagonist, bicuculline, and the blockers of the GABA-receptor-coupled chloride channel, picrotoxin and pentylenetetrazol, produced a dose-dependent proconflict effect.
(18) In the second test, the cats injected with picrotoxin crossed to the other compartment while the subjects injected with saline did not move.
(19) The immediate posttraining administration of the GABA antagonist, bicuculline, or of the Cl-channel blockers, picrotoxin or Ro 5-4864, enhances memory.
(20) The action of strychnine and picrotoxin on the values of different reflex components was not identical; this pointed to a different localization of the inhibitory action of GABA and glycine in the central link of the somatosympathetic reflex arch.